Climate Change

What is Climate Change?

Climate includes patterns of temperature, precipitation, humidity, wind and seasons. "Climate change" affects more than just a change in the weather, it refers to seasonal changes over a long period of time. These climate patterns have a significant impact on humans, as well as on the environment around us.

As so many systems are tied to climate, a change in climate can affect many related aspects of where and how people, plants and animals live, such as food production, availability and use of water, and health risks. For example, a change in the usual timing of rains or temperatures can affect when plants bloom and set fruit, when insects hatch or when streams are their fullest. This can affect historically synchronized pollination of crops, food for migrating birds, spawning of fish, water supplies for drinking and irrigation, forest health, and more.

How is weather different from climate?

Weather can change from hour-to-hour, day-to-day, and season-to-season. Weather is what we hear about on the television news every night. It includes wind, temperature, humidity, atmospheric pressure, cloudiness, sunshine and precipitation.

Climate is the average weather for a particular region over a long period of time. Climate describes the total of all weather occurring over a long period of years in a given place. This includes average weather conditions, regular weather seasons (winter, spring, summer, and fall), and special weather events (like tornadoes and floods). Climate tells us what it's usually like in the place where you live.

What causes climate change?

According to the Intergovernmental Panel on Climate Change (IPCC), climate change can be “due to natural variability or as a result of human activity."

There is new and stronger evidence that most of the warming over the last 50 years is due to human activities. In its 2007 report to the United Nations, the IPCC concluded that it is more than 90 percent likely that the accelerated warming of the past 50-60 years is due to human contributions.

These contributions include increased levels of “heat-trapping” gases known as greenhouse gases, such as carbon dioxide in the Earth’s atmosphere. One of the biggest ways people contribute to greenhouse gases is by burning fossil fuels. We use coal, oil, and natural gas to generate electricity, heat our homes, power our factories, and run our cars.

Changing land use patterns contribute, too. Trees and other plants use carbon dioxide and give off oxygen. When trees are cut down for development, agriculture, and other purposes, they’re no longer available to take carbon dioxide out of the air, and actually release carbon dioxide as they decay or burn.

As the levels of carbon dioxide and other greenhouse gases increase, more heat is “trapped” and global temperatures rise. This warming causes significant changes in the timing and length of the seasons as well as the amount and frequency of precipitation.

Health Impacts of Climate Change

Heat waves, severe storms, air pollution, and diseases linked to climate already threaten people's health in many areas of the world. Global climate change will increase these threats. Some people will be particularly at risk, especially those who are poor, very young or elderly, or disabled, or those who live in coastal areas or big cities. Some potential impacts include:

Temperature–Related Illnesses

Climate change may directly affect human health through increases in average temperature. Such increases may lead to more extreme heat waves during the summer while producing less extreme cold spells during the winter. Rising average temperatures are predicted to increase the incidence of heat waves. Heat waves are uncomfortable for everyone, but for infants and young children, the elderly, and people who are already sick, they can be especially dangerous. Extreme heat can cause illnesses such as heat cramps, heat stroke, and even death. In fact, heat waves cause more deaths in the United States every year than hurricanes, tornadoes, floods, and earthquakes combined.

Air Quality

Certain kinds of air pollutants, like ozone, can make asthma and other lung conditions worse. Ozone found high in the atmosphere is called "good ozone" because it protects life on Earth from the sun's harmful ultraviolet rays. Ozone can also be found close to the surface of the Earth, where it is considered “bad ozone” because it's the main ingredient of smog and is harmful for people to breathe. Climate change is likely to increase the amount of ground-level ozone in the air because more ozone is created when the temperature is warm. Another pollutant of concern is particle pollution or Particulate Matter (PM). Particulate matter is a mixture of extremely small particles and liquid droplets. When breathed in, these particles can reach the deepest regions of the lungs. Exposure to particle pollution is linked to a variety of significant health problems.

Spreading Diseases

Climate change may increase the risk of some infectious diseases, particularly those diseases that appear in warm areas and are spread by mosquitoes and other insects. These "vector-borne" diseases include malaria, dengue fever, yellow fever, and encephalitis. Also, algal blooms could occur more frequently as temperatures warm — particularly in areas with polluted waters — in which case diseases (such as cholera) that tend to accompany algal blooms could become more frequent. Higher temperatures, in combination with favorable rainfall patterns, could prolong disease transmission seasons in some locations where certain diseases already exist.

So, What Can You Do?

Next time you replace your most frequently used automobile, purchase a fuel-efficient car, rated up to 32 mpg or more.